1. Field of the Invention
The present invention relates to a refrigerating machine that has an outdoor unit and a plurality of indoor units and enables these plural indoor units to carry out heating operation and cooling operation in a mixing style.
2. Description of the Related Art
There is generally known a refrigerating machine in which an outdoor unit is connected to a plurality of indoor units through an inter-unit pipe comprising a high-pressure gas pipe, a low-pressure gas pipe and a liquid pipe so that one of cooling operation and heating operation can be carried out in the plural indoor units at the same time or both cooling operation and heating operation can be carried out in the plural indoor units in a mixing style at the same time (see Japanese Patent No. 2804527). In this specification, it is assumed that the refrigerating machine contains a heat pump.
This type of refrigerating machine has a problem that when the temperature of refrigerant at the exit of a heat exchanger used as a radiator (hereinafter referred to as “radiation side heat exchanger”) increases, the specific enthalpy of the refrigerant at the exist of the radiation side heat exchanger increases, and thus the wetness degree of refrigerant at the entrance of a heat exchanger used as an evaporator (hereinafter referred to as “evaporation side heat exchanger”) is reduced, so that the performance of the refrigerating machine is lowered.